Generally, a multi-vision indicates a digital image device provided with a plurality of display modules, and configured to display an image on the plurality of display modules in an enlarged manner, or to display an individual image on each of the display modules.
The multi-vision is being widely used not only for broadcasting programs in a public place, but also for advertisements and announcements using a digital signage screen. Further, the multi-vision may be utilized as an interworking service among various screen terminals, such as an N-screen service.
FIG. 1 illustrates an example of a multi-vision in accordance with the conventional art.
As shown in FIG. 1, the multi-vision, provided with a plurality of display modules, may display a single image on the plurality of display modules, or display different images on the plurality of display modules. The plurality of display modules (sets) may be connected to each other in a daisy chain form, i.e., in series. The multi-vision may be an outdoor display device such as a digital signage, or may be a home display device for a large screen.
A method of allocating an ID to each display module (set) of the multi-vision is as follows. IDs are individually allocated to the respective display modules by using an IR receiver. Alternatively, a plurality of multi-vision sets are connected to each other in a daisy chain form, and then IDs are sequentially allocated to the multi-vision sets in a horizontal-direction writing manner.
FIG. 2 is a configuration view of a single multi-vision set.
As shown in FIG. 2, in each multi-vision set, a first communication terminal (Rx) of a display module 10 is connected to an IR (infrared) communication line, thereby receiving a remote controller signal (IR signal). And communication terminals (communication ports) (Rx, Tx) of the display module 10 receive ID values from an external device (e.g., PC), through an input terminal (IN) of an RS-232 communication port 12, or generates and transmits an ID (ID+1) for a next multi-vision set, through an output terminal (OUT). A switch 11 is provided between the communication terminals (Rx, Tx).
The switch 11 is controlled under control of a controller (not shown), thereby switching the Rx communication terminal and the Tx communication terminal from each other when IDs are received and transmitted. That is, the switch 11 changes the current communication terminal into the Rx communication terminal when receiving an ID, but changes the current communication terminal into the Tx communication terminal when transmitting an ID to the next multi-vision set.
FIG. 3 is a configuration view of a plurality of multi-vision sets connected to each other in a daisy chain form.
Referring to FIG. 3, in all of the multi-vision sets, Rx communication lines are connected to each other such that remote controller operations are applied at a time, and RS-232 Tx and Rx communication lines are also connected to each other.
A user may connect the IR receiver to a first multi-vision set, and may transmit an IR signal indicating start of ID allocation by using a remote controller. Once the IR signal is received by the IR receiver, the IR signal is input to all of the multi-vision sets, since the IR line is connected to all of the multi-vision sets. Upon input of the IR signal, a controller of each multi-vision set controls the switch 11 such that the communication terminal (Rx) of the display module 10 is connected to the RS-232 communication line.
When an ID is set through an external device, the ID is input through an RS-232 communication port 12, and then is input to the communication terminal (Rx) of the first display module 10. However, since the RS-232 communication lines are bypassed, the allocated ID is input to other display modules as well as the first display module 10. Consequently, the same ID is allocated to all of the multi-vision sets.
Each multi-vision set, which has received the ID, transmits a value corresponding to its ID+1, to a next multi-vision set, sequentially. In this case, each multi-vision set changes the communication terminals to Tx from Rx by controlling the switch 11, and then transmits a value of its ID+1 to the next multi-vision set. As a result, since the communication terminals of all the multi-vision sets are changed to Tx, each multi-vision set cannot transmit the value (ID+1) created by itself, to the next multi-vision set. For instance, even if the first multi-vision set receives an ID and then transmits the value (ID+1) to the second multi-vision set through the communication terminal (Tx), the communication terminal (Rx) of the second multi-vision set is blocked. Thus, the second multi-vision set cannot be allocated with the value of ID+1.
Especially, in such a communication structure, it is impossible to check a reference multi-vision set, since the IR communication lines are connected to each other. The reference multi-vision set indicates a set where ID setting is started, which means a set having an ID value of ‘1’.